#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <fstream>
#include <set>

using namespace std;

void print(const vector<string> &input)
{
    bool even = false;
    for (int i = 0; i < input.size(); i++) {
	istringstream iss(input[i]);
	int cur = 0; 
	string str;
	while (iss >> str) {
	    cur++;
	    if (even && (cur%2 == 0)) continue;
	    cout << str << " ";
	}
	even = even == false ? true : false;
	cout << endl;
    }

}

int main(int argc, char **argv)
{
    vector<string> input;
    input.push_back("this is first line");
    input.push_back("this is second line");
    input.push_back("this is third line");
    input.push_back("this is forth line");
    input.push_back("this is fifth line");
    print(input);
}
